activity stimulates the production of natural chemical messengers in the brain called ‘excitatory transmitters’. These transmitters can become toxic to the brain. Scientists at the University of Rochester Medical Center have recently discovered a system that drains waste products from the brain as we sleep. Cerebrospinal fluid, a clear liquid surrounding the brain and spinal cord, moves through the brain along a series of channels that surround the blood vessels. The brain’s glial cells manage the system and so the researchers called it the ‘glymphatic system’. It is thought that it is particularly active during deep sleep and helps to remove a toxic protein called beta-amyloid from brain tissue. This protein is renowned for accumulating in the brains of patients with Alzheimer’s disease.7
Learning and Memory Consolidation
Sleeping sorts out our mental filing cabinets so we wake up feeling mentally sharp and clear. I’m going to tell you more about this vital function later because for some people it is the reason why they wake up exhausted, feeling as if they’ve been thinking all night or even oversleeping in a vain attempt to recoup energy.
Many others and I also believe that sleep serves a couple more vital roles. These roles are perhaps not as well validated by Western science but have been identified and explored by older sciences such as Indian Ayurveda (medicine) and Traditional Chinese Medicine (TCM) for thousands of years.
Restore Life Force Energy
Time and again my work has shown how people are able to regain some special part of themselves when they start sleeping well. For example, the actress/singer who was too exhausted and depressed to get out of bed who started singing again and signed a record deal within six months; or the stressed mother who sets up her own company. It’s more than just having a good night’s sleep and more energy, it’s a rekindling of passion, inspiration and courage.
Pure sleep is an awakening of spiritual energy.
Self-healing
The healing benefits of sleep are related to all of the above functions but I feel they deserve highlighting. What happens when you sleep on a problem and wake up feeling better? Or when you go to bed with aches and pains and wake up with no pain at all? Or if you cut yourself and wake up and the wound has virtually disappeared? The body is constantly renewing itself. Up to 75 trillion cells repairing, regenerating and rebalancing. This process is fast-tracked when you sleep.
The Journey Through the Night
There’s a kind of magic that takes place when you sleep. Sleep is not one constant state, but rather a progression through various states with extremely unique characteristics.
Earlier I mentioned the 90-minute ultradian cycle, describing it as setting the hum of your energy. This cycle continues throughout the night as we sleep in 90-minute cycles. Disruption of these cycles when we cross time zones causes sleep disruption and jetlag. The hormones, neurotransmitters and the circadian timer in the pineal gland beautifully orchestrate all this activity.
This important gland in the brain’s hypothalamus is also known in Eastern medicine as ‘the third eye’, and it is sensitive to the daily cycle of light and dark. So when the light level entering our eyes and hitting the light-sensitive retina at the back of the eye drops below 200 lux, this switches on the circadian timer and stimulates the production of the all-important sleep hormone melatonin. The healing PNS becomes more active and the sleep cycle is switched on. The awake cycle is stimulated as light levels increase via a group of cells, also located in the hypothalamus, called the Suprachiasmatic nucleus (SCN). The SCN suppresses the production of melatonin and signals the body that it’s time to wake up. The active ‘doing’ SNS switches on, body temperature increases and hormones such as cortisol are produced to get us going. Every organ system in the body receives a signal to up-regulate (get active) or down-regulate (slow down) and in this way our physiology is kept in an optimal state of balance and fine-tuning.
Western sleep science is relatively young and we are still learning more. Spending a night in a sleep clinic generates polysomnograph recordings, which are measurements of brain wave activity during sleep. The patient is wired up to monitoring equipment with electrodes and an EEG (electroencephalogram tracing of the bioelectric activity of the brain) is produced, which informs the sleep clinician about the person’s sleep patterns and potential disorders. In 1937 Alfred Lee Loomis, an American also known for significant work in developing radar, first described the stages of sleep. Loomis and his team used EEG recordings to identify five different levels of sleep.8 In 1953, another team of scientists discovered that REM (rapid eye movement) sleep was a distinct state, leading to a rethinking of the way sleep was designed and giving us the model we use today.9
The Five Stages of Sleep
So let’s look at each sleep stage in turn as it may help you to get a sense of why our sleep (and energy levels) may be less than ideal.
In total, there are five stages of sleep that can be easily distinguished from each other: two are light sleep, the following two are slow-wave or deep sleep and the fifth is a short 15-minute burst of REM sleep. Sleep can also be divided into two entirely different states:
1 REM (rapid eye movement) sleep
2 non-REM (nREM) sleep
Additionally, non-REM is subdivided into four sub-stages, which are distinguishable by levels of brain-wave activity. The sleep science community has more recently combined non-REM stages 3 and 4 into one stage (stage 3).
A typical night’s sleep consists of about 75 per cent non-REM and 25 per cent REM sleep. The 90-minute cycle repeats throughout the night, each time taking us through the five layers from light to deep sleep and REM sleep. Although I keep emphasising the importance of deep sleep, each of these layers is vital and we have to go through them all while we sleep.
Non-REM Sleep
The first four phases of sleep are non-REM sleep and during these phases, unlike REM sleep, we can move around. Neck and jaw movements are the most common movements. If you suffer from teeth grinding (bruxism) or restless legs syndrome (RLS) both of these are more likely to be evident in the first two stages.
Fully Alert and Awake
In this stage of full consciousness, an EEG brain trace would show a predominance of beta-wave activity. This, of course, is where we spend most of our waking hours. This is the thinking, information processing and mentally alert mode, apparently processing 30,000–50,000 thoughts per day. This is the most overworked layer of our consciousness and one that has started to intrude into our sleep, as you will now see.
Stages 1 and 2 – Light Sleep
These are the first phases of sleep that we enter from being fully awake and alert and here there is predominantly alpha wave activity. Sleep is light and lasts a few minutes, and can be easily interrupted by a gentle nudge, snoring or even – very commonly – thoughts. These sleep phases are initiated when your melatonin levels and sleep debt (level of sleepiness built up throughout the day) are at their highest and, while it could be the easiest phase to slide into, it must be entered with care.
By this I mean falling asleep on the sofa in front of the TV in the evening can sabotage your efforts to subsequently enter the next stages of sleep, as you can deplete your melatonin levels and then find you just can’t get to sleep. This problem is exacerbated if you then sneak a look at your emails or social media notifications, as blue light is a potent suppressor
